Heat and moisture transfer apparatus integrated into an exterior partition

ABSTRACT

Systems, apparatus and methods that may be used to integrate a heat and moisture exchange system with the heating, ventilation and air conditioning system of a building or other enclosed space, without requiring installation within the walls or other structural portions of the building.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/682,230, filed Aug. 11, 2012, which is hereby incorporated by reference. This application also incorporates by reference for all purposes U.S. patent application Ser. No. 13/747,218, filed Jan. 22, 2013, U.S. Pat. No. 6,178,966, issued Jan. 30, 2001 and U.S. Patent Publication No. 2007/0151447, published Jul. 5, 2007.

BACKGROUND

In centrally heated or cooled buildings, fresh air or “makeup air” is typically added continuously to the total volume of circulated air, resulting in some previously heated or cooled air being exhausted from the building space. This can result in an undesirable change of energy and humidity within the building. Heat exchangers are commonly used in the exhaust air and makeup airflow paths of these systems to recover some of the energy from the exhaust air and to induce warmer makeup air during heating processes and cooler makeup air during cooling processes.

Materials used for heat exchangers commonly include metal foils and sheets, plastic films, paper sheets, and the like. Good heat exchange is generally possible with these materials, but significant moisture exchange cannot easily be performed. Desiccants, or moisture adsorbing materials, are occasionally employed to transfer moisture. With this method, the desiccant merely holds the moisture. To effectively transfer moisture between gas streams, the desiccant must be relocated from the gas stream of higher moisture content to the gas stream of lower moisture content, requiring an additional input of mechanical energy. With many desiccant materials, satisfactory performance can be achieved only with the input of additional thermal energy to induce the desiccant to desorb the accumulated moisture.

Heat and moisture exchange are both possible with an exchange film made of paper. However, water absorbed by the paper from condensation, rain, or moisture present in the air can lead to corrosion, deformation, and mildew growth, and, hence, deterioration of the paper exchange film.

The various types of heat and moisture exchangers in common usage are generally contained within an opaque metal housing and located at or near the building air-handling units in the mechanical room, basement, or rooftop of the building. The nature of moisture exchange requires a very large surface area in contact with the gas stream, and, consequently, so-called total heat exchangers are often very large in size when compared to heat-only exchangers. A larger exchanger in the conventional locations requires additional mechanical room space and/or additional load-bearing capacity of the roof in the case of a roof-top unit.

Porous polymeric or ceramic films are capable of transferring both heat and moisture when interposed between air streams of differing energy and moisture states. A system for heat and moisture exchange employing a porous membrane is described in Japanese Laid-Open Patent Application No. 54-145048. A study of heat and moisture transfer through a porous membrane is given in Asaeda, M., L. D. Du, and K. Ikeda. “Experimental Studies of Dehumidification of Air by an Improved Ceramic Membrane,” Journal of Chemical Engineering of Japan, 1986, Vol. 19, No. 3. A disadvantage of such porous composite film is that it also permits the exchange of substantial amounts of air between the gas streams, as well as particles, cigarette smoke, cooking odors, harmful fumes, and the like. With respect to building indoor air quality, this is undesirable. In order to prevent this contamination of make-up air, the pore volume of a porous film is preferably no more than about 15%, which is difficult and expensive to achieve uniformly. Furthermore, a porous film made to a thickness of 5 to 40 micrometers in order to improve heat exchange efficiency tears easily and is difficult to handle.

U.S. Pat. No. 6,178,966 to Breshears addressed the shortcomings described above by describing an improved apparatus for enabling heat and moisture exchange between makeup and exhaust air streams in the heating and air conditioning system of a structure. The apparatus included a rigid frame for holding a pair of light transmitting panes, the frame and panes collectively defining an interior cavity within the apparatus. The apparatus could be integrated into the exterior walls of a building. The light transmitting properties of the panes allow incident solar radiation to permeate the panels, creating a more natural ambient environment in the interior of the structure adjacent with the panel, as well as raising the temperature of the air stream and the water vapor permeable barrier to further enhance the exchange of moisture through the barrier.

U.S. Pat. No. 6,178,966 discloses in part a heat and moisture exchanger apparatus configured to be integrated into transparent exterior walls of a building. U.S. patent application Ser. No. 13/747,218 expands the teachings of U.S. Pat. No. 6,178,966 by describing in part an exchanger apparatus configured to be integrated within an opaque building element, such as within the interior walls, floors, ceilings, and/or plenum spaces of a building.

In some situations, however, it may not be practical or desirable to incorporate a heat and moisture exchange system into the walls (whether transparent or opaque), floors, ceilings, or plenum spaces of a building. For example, retrofitting an existing building with a system disposed in one or more of these locations may be prohibitively expensive, time-consuming or inconvenient. For similar reasons, in some cases it may not be desirable to integrate an exchanger system within the structural portions of a building during new construction. Accordingly, there is a need for an effective heat and moisture exchange system that may be integrated or otherwise associated with a building without these drawbacks.

SUMMARY

The present teachings disclose a heat and moisture exchanger system that may be disposed on a building rooftop or otherwise near the building, and then integrated with the heating, ventilation and air conditioning system of the building.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically depicts a system for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

FIG. 2 schematically depicts another system for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

FIG. 3 depicts an exemplary apparatus for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

FIG. 4 depicts another exemplary apparatus for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

FIG. 5 depicts yet another exemplary apparatus for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

FIG. 6 is a cross sectional view of an exemplary heat and moisture exchanger module, taken along the line 6-6 in FIG. 4.

FIG. 7 depicts still another exemplary apparatus for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

FIG. 8 depicts still another exemplary apparatus for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

FIG. 9 depicts still another exemplary apparatus for exchanging heat and moisture between incoming and outgoing air streams of an enclosed space, according to aspects of the present teachings.

DETAILED DESCRIPTION

The present teachings describe systems, apparatus and methods that may be used to integrate a heat and moisture exchange system with the heating, ventilation and air conditioning system of a building or other enclosed space, without requiring installation within the walls, ceilings, floors, plenum spaces, or other structural portions of the building or enclosed space.

I. Definitions

In this disclosure, the terms “HVAC,” “HVAC unit,” “ventilation system” and “air conditioning system” may be used interchangeably to describe a system used to refresh the air within a building so that it remains continuously pleasant and healthy for the building occupants to breathe. Depending on the location of the building, seasonal climate variations, local air quality, and other factors, a particular system may not perform all of the functions of heating, ventilation and air conditioning at a particular time, regardless of the term used to describe the system.

II. General Considerations

This section describes various general considerations that apply to certain aspects of the present teachings; see FIGS. 1-2.

FIG. 1 is a schematic diagram depicting a system, generally indicated at 100, for enabling heat and moisture exchange between air streams entering and leaving a building, according to aspects of the present teachings. System 100 includes an enclosed space 102, such as a building which requires ventilation, an exchanger partition 104, and an HVAC unit 106 associated with the building. Exchanger partition 104 will typically be disposed in a location adjacent to, but outside the building, and conveniently close to HVAC unit 106. For example, if HVAC unit 106 is disposed on the building rooftop, exchanger partition 104 may also be disposed on the building rooftop. An exchanger partition such as partition 104 can also be referred to as an exchanger screen, and in some cases may serve various screening functions, such as containing the noise produced by an HVAC unit, screening the HVAC unit from wind, rain or sun, or screening an unrelated portion of a building from noise or the elements.

Exchanger partition 104 may be modular, i.e., partition 104 may include a plurality of modules that may be interconnected or otherwise associated with each other. This modularilty will be described in more detail below in Section III. In some cases, partition 104 may include just a single module. In any case, whether the partition includes just one or a plurality of modules, each module of the partition defines an interior channel, i.e., each module defines an interior volume through which air may pass.

A membrane, permeable to water vapor and substantially impermeable to constituent gases of air, is disposed within each module and divides the interior channel of the module into a first sub-channel through which a first air stream may pass and a second sub-channel through which a second air stream may simultaneously pass. As a result, partition 104 is configured to enable heat and moisture exchange between air streams traveling through the first and second sub-channels of the partition. As will be described below, these will be the air streams entering and leaving enclosed space 102.

Partition 104 includes at least one air inlet, generally indicated at 108, and typically will include one air inlet for each module of the partition. Each air inlet is configured to allow ingress of supply air from an environment external to the building into one of the first sub-channels. A return air manifold, depicted by arrow 110, is configured to receive return air from an interior environment of the building or other enclosed space 102, and to direct a portion of the return air into each of the second sub-channels of partition 104.

After passing through air inlet(s) 108, fresh supply air will pass through the first sub-channels of partition 104, and after passing through return air manifold 110, return air from the enclosed space will pass through the second sub-channels of partition 104, whereupon heat and moisture may be exchanged between these two air streams, through the membranes disposed between the first and second sub-channels. Fresh supply air that has received heat and/or moisture from return air in this manner will be referred to as “reconditioned supply air.”

After passing through partition 104, the reconditioned supply air will pass through a supply air manifold, indicated by arrow 112, which is configured to receive the reconditioned supply air from each of the first sub-channels and to direct the reconditioned supply air from the first sub-channels to HVAC unit 106, which also may be referred to as air conditioning unit 106. The process of exchanging heat and/or moisture between the return air stream and the supply air stream typically reduces energy costs by bringing the supply air closer to the desired temperature and humidity of the air within the enclosed space than it would be in the absence of the presently disclosed exchanger system.

After passing through the second sub-channels, the return air will have altered temperature and/or moisture content as a result of exchanging heat and/or humidity with the supply air stream, and may be referred to as “reconditioned return air.” Typically, partition 104 will include one or more reconditioned return air outlets, generally indicated at 114, each providing egress of reconditioned return air from one of the partition modules into the environment external to the building.

A number of additional elements may be incorporated into system 100 to improve or alter its performance. For example, system 100 may include a reconditioned return air manifold, indicated by arrow 116. The reconditioned return air manifold is configured to receive reconditioned return air from each of the second sub-channels, and to direct the reconditioned return air toward a return air flow control damper 118. The return air flow control damper is configured to direct a first portion of the reconditioned return air into the air conditioning unit, and a second portion of the reconditioned return air into the environment external to the building. In other words, return air flow control damper 118 splits the reconditioned return air into a portion to be recirculated to the interior space (e.g., the building interior), and a portion to be exhausted and not recirculated. This can be accomplished, for example, with an adjustable partition within the damper, to direct different fractions of the incoming air along two diverging paths.

In addition to the function of splitting the reconditioned return air into two portions, the return air flow control damper also may be configured to provide control over the overall rate of return air flowing out of enclosed space 102, and/or over the rate of reconditioned return air flowing from the damper into the air conditioning unit. This can be accomplished, for example, with one or more adjustable apertures leading into and/or out of the damper, to limit the rate of air flow through the damper.

In some cases when multiple exchanger modules are used to construct partition 104, reconditioned return air manifold 116 may define a cross-sectional area that increases as the reconditioned return air manifold extends from each successive module toward the return air flow control damper, to accommodate the additional return air that passes into the reconditioned return air manifold from each successive module. Similarly, again in cases when multiple exchanger modules are used to construct partition 104, supply air manifold 112 may be constructed to define a cross-sectional area that increases as the supply air manifold extends from each successive module toward air conditioning unit 106, to accommodate the additional reconditioned supply air received from each successive module. Manifolds with varying cross-sectional areas will be described in further detail below in Section III.

System 100 also may include a supply air flow control damper 120 disposed within or fluidicially connected with supply air manifold 112. Supply air flow control damper may be used to control the rate at which reconditioned supply air flows into air conditioning unit 106, and thus also to control the rate at which fresh supply air flows into partition 104. The combination of return air flow control damper 118 and supply air flow control damper 120 can be used to limit the flow of air through each portion of system 100.

System 100 also may include one or more fans to facilitate the flow of air through the system. For example, a supply air fan 122 may be disposed within or in fluid communication with supply air manifold 112, and a return air fan 124 may be disposed within or in fluid communication with reconditioned return air manifold 116. These fans may have adjustable speeds, and may be used in conjunction with the air flow control dampers to completely control the rate of air flow through system 100.

As described above, air conditioning unit 106 may receive both reconditioned return air from return air flow control damper 118, and reconditioned supply air from supply air flow control damper 120. Accordingly, air conditioning unit 106 may include a mixing mechanism 126 configured to mix the reconditioned return air and the reconditioned supply air together before recirculating the mixture to enclosed space 102. For example, mixing mechanism 126 may take the form of a plenum or a set of dampers configured to merge the reconditioned air streams together.

Air conditioning unit 106, also called an HVAC unit, may be of any known type, and will generally be configured to heat, cool, humidify, dehumidify and/or filter the air that passes through it, as determined by a particular situation. In system 100, the energy burden placed on the HVAC unit is expected to be lessened by the reconditioning of the supply air within exchanger partition 104. In any case, after appropriate additional conditioning by unit 106, the reconditioned air will be transported back into enclosed space 102, for example, by a reconditioned air duct indicated by arrow 128.

FIG. 2 is a schematic diagram depicting another system, generally indicated at 200, for enabling heat and moisture exchange between air streams entering and leaving a building, according to aspects of the present teachings. System 200 is similar in many respects to system 100 described previously. Specifically, system 200 includes an enclosed space 202, an exchanger partition 204, and an air conditioning unit 206 associated with the enclosed space. Exchanger partition 204 will typically be disposed in a location outside the enclosed space, and conveniently close to air conditioning unit 206. For example, air conditioning unit 206 and exchanger partition 204 may both be disposed on a building rooftop.

Exchanger partition 204 may be modular, i.e., may include a plurality of exchanger modules that may be interconnected or otherwise associated with each other. This modularilty will be described in more detail below with reference to the specific exemplary embodiments of Section III. In some cases, partition 204 may include just a single module. In any case, each module of the partition defines an interior channel, i.e., each module defines an interior volume through which air may pass.

A membrane, permeable to water vapor and substantially impermeable to constituent gases of air, is disposed within each module of system 200 and divides the interior channel of the module into a first sub-channel through which a first air stream may pass and a second sub-channel through which a second air stream may simultaneously pass. Often, a plurality of membranes will be used to divide the interior channel of each module into several pairs of adjacent first and second sub-channels. In any case, partition 204 is configured to enable heat and moisture exchange between adjacent air streams traveling through the first and second sub-channels of the partition.

Partition 204 includes at least one air inlet, generally indicated at 208, and typically will include one air inlet for each module of the partition. Each air inlet is configured to allow ingress of supply air from an environment external to the building into the first sub-channels of one of the exchanger modules. A return air manifold, depicted by arrow 210, is configured to receive return air from an interior environment of the building or other enclosed space 202, and to direct a portion of the return air into each of the second sub-channels of partition 204.

Return air manifold 210 includes a return air flow control damper 216. The return air flow control damper is configured to direct a first portion of the return air into air conditioning unit 206, and a second portion of the return air into the exchanger partition. In other words, return air flow control damper 216 splits the return air into a portion to be recirculated to the interior space (e.g., the building interior), and a portion to be used for reconditioning the supply air and then exhausted into the external environment, for instance through return air outlets associated with each exchanger module and generally indicated at 214. This splitting of the return air can be accomplished, for example, with an adjustable partition within the damper, to direct different fractions of the incoming air along two diverging paths. Thus, the function of return air flow control damper 216 is similar to the function of return air flow control damper 118 of system 100, except that in system 200 the return air is split before passing through the exchanger partition, whereas in system 100 the return air is split after passing through the exchanger partition.

After passing through air inlet(s) 208, fresh supply air will pass through the first sub-channels of partition 204, and after passing through return air manifold 210, the portion of the return air from the enclosed space which is directed toward partition 204 will pass through the second sub-channels of partition 204, whereupon heat and moisture may be exchanged between these two air streams, through the membranes disposed between the first and second sub-channels. Supply air that has exchanged heat and/or moisture with return air in this manner will be referred to as “reconditioned supply air,” and the corresponding return air, which exchanged heat and/or moisture with the supply air, will be referred to as “reconditioned return air.”

After passing through partition 204, the reconditioned supply air will pass through a supply air manifold, indicated by arrow 212, which is configured to receive the reconditioned supply air from each of the first sub-channels and to direct the reconditioned supply air from the first sub-channels to air conditioning unit 206. As described previously, this exchange process is expected to reduce energy costs by bringing the supply air closer to the desired temperature and humidity of the air within the enclosed space than it would otherwise be. A supply air flow control damper 220 and/or a supply air fan 222 may be used to control the rate of supply air flow through system 200, as described previously with respect to supply air flow control damper 120 and/or a supply air fan 122 of system 100.

After passing through the second sub-channels, the reconditioned return air will exit the partition by passing through one or more reconditioned return air outlets, generally indicated at 214, each providing egress of reconditioned return air from one of the partition modules into the environment external to the building. Meanwhile, a second portion of the return air, which was split toward air conditioning unit 206 by return air flow control damper 216, will proceed into the air conditioning unit via a return air conduit 218. This may be facilitated by a return air fan 224.

As in the case of the HVAC unit of system 100, air conditioning unit 206 may include a mixing mechanism 226 configured to mix the return air (in this case, not reconditioned) and the reconditioned supply air together before recirculating the mixture to enclosed space 202. For example, mixing mechanism 226 may take the form of a plenum or a set of dampers configured to merge the return air stream and the reconditioned supply air stream together. After a desired type and amount of additional conditioning by air conditioning unit 206, the fully reconditioned, which contains both supply air and return air, will be transported back into enclosed space 202, for example, by a reconditioned air duct indicated by arrow 228.

III. Examples

This section describes more specific examples of heat and moisture exchangers incorporating some or all of the general principles described above in Section II; see FIGS. 3-9.

FIG. 3 depicts an apparatus, generally indicated at 300, for enabling heat and moisture exchange between air streams entering and leaving a building, according to aspects of the present teachings. As described in detail below, apparatus 300 incorporates many of the principles and features described previously in Section II.

Specifically, apparatus 300 includes a partition, generally indicated at 302, configured to be disposed outside a building in the vicinity of an air conditioning unit of the building. Partition 302 is modular, and includes a plurality of substantially identical partition modules 304. Each module defines an interior channel, and a membrane disposed within each module divides the interior channel into a first sub-channel through which an incoming air stream may pass and a second sub-channel through which an outgoing air stream may simultaneously pass. The interior structure of modules 304 will be described in more detail below with respect to FIG. 6. In any case, each membrane is characterized by being permeable to water vapor and substantially impermeable to constituent gases of air.

Each of modules 304 includes a fresh air inlet 306 configured to allow ingress of fresh air into the first sub-channel, and an exhaust air outlet 308 configured to allow egress of exhaust air out of the second sub-channel. The fresh air that enters the first sub-channel is the incoming air stream, and the exhaust air that leaves the second sub-channel is the outgoing air stream. A supply air conduit 310 is configured to connect the first sub-channel of each module to a supply air port 312 configured to interface with the air conditioning unit, and thus to transport the incoming airstream from the partition to the supply air port. A return air conduit 314 is configured to connect the second sub-channel of each module to a return air port 316 configured to interface with the air conditioning unit, and thus to transport the outgoing airstream from the return air port to the partition.

A supply air flow control damper, schematically depicted at 318, may be disposed between partition 302 and supply air conduit 310, and a return air flow control damper, schematically depicted at 320, may be disposed between partition 302 and return air port 316. In the example depicted in FIG. 3, these flow control dampers perform the function of limiting the air flow rate to and from the air conditioning unit. In addition, a supply air fan, schematically depicted at 322, may be disposed between partition 302 and supply air conduit 310, and a return air fan, schematically depicted at 324, may be disposed between partition 302 and return air port 316. Fans 322 and 324 may be used to increase the air flow rates to and from the air conditioning unit. The combination of the flow control dampers and the fans thus may be used to control the air flow rates within apparatus 300 to any desired degree.

Both the supply air conduit and the return air conduit may have cross-sectional areas that vary with position, to accommodate the changing amounts of air in the conduits. Specifically, as depicted in FIG. 3, if supply air conduit 310 defines a length dimension corresponding to a direction of air flow from partition 302 toward supply air port 312, a cross-sectional area of the supply air conduit may increase along the length dimension to accommodate supply air received from successive modules 304. Similarly, also as depicted in FIG. 3, if return air conduit 314 defines a length dimension corresponding to a direction of air flow from return air port 316 toward modules 304, a cross-sectional area of the return air conduit decreases along the length dimension as the return air passes into successive modules.

Apparatus 300 may be supported on a flat surface such as a building rooftop by any suitable support structure, one example of which is the scaffold brace depicted at 326 in FIG. 3. A suitable support structure may be constructed of metal, such as steel, aluminum, or some other suitably rigid metal, painted wood, or any other material capable of supporting the apparatus and resisting environmental elements. Alternatively, the partition or modular panel array of the apparatus may be supported by other structures or elements adjacent to it.

Various structures may be used to direct the incoming and outgoing air streams to and from the associated sub-channels of the partition modules. For example, a header or header structure may be included at one end of an exchanger partition, as indicated schematically at 328 in FIG. 3. Header 328 is configured to accept the supply air flow from the plurality of supply air sub-channels within the exchanger modules, and to direct them into the supply air manifold. Similarly, header 328 is configured to accept the exhaust/return air stream from the return air manifold and to direct that air flow into the plurality of exhaust air sub-channels within the exchanger modules. The structure and function of a suitable header will be further described below with reference to the example illustrated in FIG. 4.

FIG. 4 depicts another heat and moisture exchange apparatus, generally indicated at 400, according to aspects of the present teachings. Apparatus 400 is generally similar to apparatus 300 depicted in FIG. 3, with two primary distinctions. First, FIG. 4 depicts a different support structure, in the form of a plurality of horizontal bracing beams 426, supporting apparatus 400. This support structure might be suitable, for example, with an exchange apparatus disposed relatively close to a vertical wall, whereas the scaffold brace 326 depicted in FIG. 3 might be more suitable with an exchange apparatus disposed relatively far from any walls.

In addition, apparatus 400 includes a supply air conduit 410 and a return air conduit 412 that each has a continuously varying cross-sectional area as the conduits traverse the length of partition 402, rather than a stepped cross-sectional area as in the case of conduits 310 and 312 of apparatus 300. The continuously varying conduits depicted in FIG. 4 still serve the purpose of accommodating air flows that change as air is received from and provided to the modules of partition 402, but may be simpler to manufacture that the stepped conduits of apparatus 300.

FIG. 5 depicts still another heat and moisture exchange apparatus, generally indicated at 500, according to aspects of the present teachings. Exchange apparatus 500 is generally similar to exchange apparatus 400, except that the orientation of various components of apparatus 500 has been rotated by 90 degrees relative to their counterparts in apparatus 400.

More specifically, apparatus 500 includes a heat and moisture exchange partition, generally indicated at 502, which includes a plurality of panelized exchanger modules 504. Modules 504 are disposed with their long axes oriented horizontally, parallel to the plane of an underlying support surface, and supply and return air streams will flow along these long axes. In contrast, the long axes of modules 404 (and of the modules of other examples taught in this disclosure), and thus the air flow directions within these other modules, are generally oriented at some angle to the plane of the underlying support surface.

Apparatus 500 also includes a supply air manifold 510 and a return air manifold 514 that are oriented with a portion of each manifold oriented substantially orthogonally to the long axes of modules 504, to span all of the modules. Again, this is distinct from the orientation of the supply and return air manifolds of the other examples disclosed by the present teachings. An orientation such as the orientation of apparatus 500 may have certain advantages, such as better accommodating a substantially vertical support structure, as depicted by vertical support beams 526 in FIG. 5. Other aspects of apparatus 500 are similar to the corresponding aspects of the other examples described in the present teachings, and will therefore not be described again with respect to apparatus 500.

FIG. 6 is a cross-sectional view of one of partition modules 404 depicted in FIG. 4, although the internal structure shown in FIG. 6 could also be used in any of the other partition modules described in this disclosure, such as modules 304, 504 (where the section would be taken vertically rather than horizontally), 704, 804 and/or 904. Each module generally includes an external housing 600, which might, for example, be constructed from a suitably rigid, durable, and weather-resistant material such as painted or coated metal, galvanized or otherwise chemically-treated metal, plastic, fiberglass, carbon, or the like.

The interior of the module may include a radiant barrier layer 602, configured to inhibit heat transfer across the barrier by thermal radiation. For example, radiant barrier layer 602 may be a highly reflective layer constructed from a material such as a thin sheet or film of metal foil (such as aluminum), or any other reflective material. Barrier layer 602 may be applied directly to the interior of external housing 600, or it may be disposed on a frame (not shown) that leaves a small air space just inside housing 600, to provide additional insulation to the module.

The interior space within the partition module defines an interior channel, generally indicated at 601. This interior channel is divided into a plurality of alternating sub-channels, generally indicated at 604, 606, by membranes 608 disposed within the interior channel of the module. Each sub-channel contains a spacer layer 610, which is configured to maintain the shape of the sub-channel and which defines a plurality of air passageways 612 within the sub-channel. Generally speaking, an incoming air stream (such as stream of supply air) passes through one set of sub-channels, such as sub-channels 604, and an outgoing air stream (such as a stream of return air) pass through the other set of sub-channels, such as sub-channels 606.

Membranes 608 are constructed to be permeable to water vapor and substantially impermeable to constituent gases of air. Suitable membranes are described, for example, in U.S. patent application Ser. No. 13/747,218, U.S. Pat. No. 6,178,966, and/or U.S. Patent Publication No. 2007/0151447, all of which have been incorporated by reference into the present disclosure. Spacer layers 610 may be constructed from any material capable of maintaining its shape over a significant period of time, while exposed to the heat and moisture expected within the module. For example, spacer layers 610 may be constructed from a suitable metallic or plastic material.

Various structures may be used to direct the incoming air stream and outgoing air stream to the associated sub-channels of the partition modules. For example, a header or header structure may be included at one end of an exchanger partition, as indicated at 328 in FIG. 3 and at 428 in FIG. 4 (similar headers may be included in any of the presently disclosed exemplary exchanger systems). The header is configured to accept the supply air flow from the plurality of supply air sub-channels within the exchanger and to direct them into the supply air manifold. Similarly, the header is configured to accept the exhaust/return air stream from the return air manifold and to direct that air flow into the plurality of exhaust air sub-channels within the exchanger.

The header may accomplish the purposes described above through a variety of configurations that serve to interconnect the supply air sub-channels of the exchanger in fluid communication with the supply air manifold while simultaneously excluding air flow from or mixing with the return air streams, and that serve to interconnect the return air sub-channels of the exchanger in fluid communication with the return air manifold while simultaneously excluding air flow from or mixing with the supply air streams. For instance, header 428 may include passageways connecting only the module sub-channels containing the incoming supply air stream to supply air conduit 410, and connecting only the module sub-channels containing the outgoing return air stream to return air conduit 414.

Conduits such as conduits 310, 314, 410 and 414, along with their counterparts in FIGS. 5, 7, 8 and 9, also may be referred to as manifolds, as they are fluidically connected with a plurality of exchanger modules, and (through an associated header) may be fluidically connected with a plurality of sub-channels of each module. Thus, each exemplary exchanger system can be viewed as including both a supply air manifold and a return air manifold, to direct air streams to and from the appropriate sub-channels of the exchanger modules, possibly in conjunction with a header structure.

FIG. 7 depicts yet another system, generally indicated at 700, for enabling heat and moisture exchange between air streams entering and leaving a building, according to aspects of the present teachings. System 700 includes a modular exchanger partition, generally indicated at 702, which includes a plurality of exchanger modules 704. Each module will typically have an internal structure similar to the structure shown in FIG. 6 and described above, i.e., each module defines an interior channel which is divided into at least a first sub-channel through which a first air stream may pass, and a second sub-channel through which a second air stream may simultaneously pass. A membrane, permeable to water vapor and substantially impermeable to constituent gases of air, is disposed within each module and divides the interior channel of the module into the first sub-channel and the second sub-channel.

As described previously, each module may include a plurality of first sub-channels and a plurality of second sub-channels, rather than just one of each. In this case, a plurality of membranes is used to divide the interior channel into the plurality of sub-channels, with one membrane separating each sub-channel from the next.

Each module 704 includes an air inlet 706, configured to allow ingress of supply air from an environment external to the building into the first sub-channels. When multiple membranes are used to create multiple first sub-channels in a module, air inlet 706 may be connected by suitably configured passageways or conduits (not shown) to the alternating first sub-channels within the module. Similarly, each module 704 includes a reconditioned return air outlet 708 providing egress of reconditioned return air from one of the modules into the environment external to the building. When a plurality of membranes are used in each module, the reconditioned return air outlets each may be connected only to the alternating second sub-channels within each module.

A supply air conduit or manifold 710 is configured to receive reconditioned supply air from each of the first sub-channels and to direct the reconditioned supply air from the first sub-channels to an air conditioning unit 718. A return air conduit or manifold 712 is configured to receive return air from the interior of the building (possibly after the return air passes through air conditioning unit 718, as depicted in FIG. 7), and to direct the return air into the second sub-channels of modules 704. The entirety of system 700, including exchanger partition 702 and air conditioning unit 718, may be disposed, for example, on a building rooftop, and supported by any suitable support structure as described previously.

Each module 704 further includes a reconditioned supply air outlet 714 connecting the module to the supply air manifold, configured to allow egress of reconditioned supply air from the first sub-channel(s) of the module, and a return air inlet 716 connecting the module to the return air manifold, configured to receive return air from an interior environment of the building and to direct at least a portion of the return air into the second sub-channel(s) of the module.

When system 700 is operating, supply air entering through supply air inlets 706 passes through the first sub-channel(s) of each module 704, while return air entering through return air inlets 716 passes through the second sub-channel(s) of each module. Heat and/or moisture is exchanged between the supply air and the return air, across the membrane(s) separating the first sub-channel(s) from the second sub-channel(s). Reconditioned supply air then passes from modules 704 to supply air manifold 710 through supply air outlets 714, while reconditioned return air passes out of modules 704 to the external environment through reconditioned return air outlets 708. In some cases, described elsewhere in this disclosure, a portion of the return air may be returned to the interior of the building, either before or after reconditioning.

In system 700, a supply air flow control damper 720 may be used to limit the flow of supply air through the system, while a supply air fan 724 may be used to increase the flow of supply air. In conjunction, damper 720 and fan 724 may be used to control the supply air flow through the system to a desired degree. Similarly, a return air flow control damper 722 and a return air fan 726 may be used to control the flow of return air through the system. A supply air duct 728 is used to direct reconditioned supply air into the interior of the building, while a return air duct 730 is used to direct return air from the interior of the building toward return air manifold 712.

As described previously, in some cases a portion of the return air from an interior enclosed space may be recirculated back into the interior enclosed space, rather than being exhausted into the exterior environment. This may reduce energy costs, as the return air may already have been conditioned to have approximately the desired temperature and humidity. Of course, a large enough fraction of supply air must be introduced to maintain an appropriate degree of overall freshness in the air within the enclosed space. FIGS. 8-9 illustrate examples where some amount of return air may be recirculated.

FIG. 8 illustrates a system, generally indicated at 800, for enabling heat and moisture exchange between air streams entering and leaving a building. System 800 includes a modular exchanger partition, generally indicated at 802, including a plurality of exchanger modules 804 disposed on a building rooftop. Each module 804 may have an internal structure as described previously and illustrated in the exemplary embodiment of FIG. 6, in which the module defines an interior channel divided by a membrane into one or a plurality of first sub-channels through which a first air stream may pass, and one or a plurality of second sub-channels through which a second air stream may pass. The membrane(s) used in each module may be constructed of any suitable material which is permeable to water vapor and substantially impermeable to constituent gases of air.

As in previously described examples, system 800 includes a plurality of supply air inlets 806 (typically at least one disposed in each module), and a supply air manifold 810 configured to receive reconditioned supply air from each of the first sub-channels of modules 804, and to direct the reconditioned supply air from the first sub-channels to an air conditioning unit 818, which may be disposed on a building rooftop or otherwise in close proximity to a building. Reconditioned supply air may enter the supply air manifold through reconditioned supply air inlets 814, which may be integrated with an appropriate air flow header system that connects the first sub-channels of the module to the supply air manifold. A supply air fan 820 and a supply air flow control damper 824 may be used collectively to control the rate of supply air flow through system 800, as has been described previously.

System 800 also includes a return air manifold 812 configured to receive return air from an interior environment of the building, and to direct a portion of the return air into each of the second sub-channels of modules 804. More specifically, a return air duct or conduit 828 receives return air from the interior environment of the building and directs it toward return air manifold 812. However, in this example, the return air manifold includes a return air flow control damper 836 configured to receive return return air that enters the return air manifold, to direct a first portion of the return air toward air conditioning unit 818, and to direct a second portion of the return air into remaining portion of return air manifold and thus into the second sub-channels, via return air inlets 816. In other words, return air flow control damper 836 splits the return air into a first portion to be recirculated, and a second portion to be exhausted.

As described previously, the return air flow control damper may be further configured to provide control over the rate of return air flowing into the return air manifold, for example using one or more variable sized apertures to limit the air flow through the damper. In some cases, the return air flow control damper also may provide the ability to control the fractions of return air directed toward the air conditioning unit and the exchanger partition, respectively. A return air fan 822 may be integrated with the return air manifold to provide additional control over the overall return air flow rate through the system.

In this example, this split of the return air stream occurs before the return air is reconditioned by passing through partition 802 and exchanging heat and/or moisture with the supply air. Thus, a first portion of the return air enters the air conditioning unit before it is reconditioned. A second portion of the return air enters the second sub-channels of the partition modules, whereupon it reconditions the supply air within the first sub-channels and is itself reconditioned in the process. A plurality of reconditioned return air outlets 808 then each provide providing egress of the reconditioned return air from one of the modules into the environment external to the building.

FIG. 9 illustrates another exemplary heat and moisture exchange system, generally indicated at 900, in which return air may be partially recirculated into an internal environment according to aspects of the present teachings. System 900 generally includes a modular exchanger partition 902 consisting of a plurality of exchanger modules 904, each of which has a supply air inlet 906 configured to receive fresh supply air from the external environment. The construction of each module 904, including its internal structure, may be generally similar to the construction of any of the previously described modules, and will not be described again in detail.

As in previous examples, a supply air manifold 910 is configured to receive reconditioned supply air from each of the first sub-channels (i.e., the supply air sub-channels) of the exchanger modules, and to direct reconditioned supply air from the first sub-channels to an air conditioning unit 918. A supply air fan 924 and/or a supply air flow control damper 926 may be used to control to flow of supply air.

In this example, however, return air is introduced into modules 904 directly from the building or other enclosed space, through a return air manifold 914. The return air manifold is configured to receive return air from an interior environment of the building, and to direct a portion of the return air into each of the second sub-channels (i.e., the return air sub-channels) of the exchanger modules. The return air introduced into modules 904 in this manner, and the supply air introduced into modules 904 through supply air inlets 906, can then exchange heat and/or moisture through any membranes present in the modules.

Furthermore, system 900 includes a reconditioned return air manifold 912 configured to receive reconditioned return air from each of the second sub-channels and to direct the reconditioned return air toward a return air flow control damper 922. Return air flow control damper 922 is configured to direct a first portion of the reconditioned return air into air conditioning unit 918, and a second portion of the reconditioned return air into the environment external to the building, for instance through an exhaust vent 928. In other words, as in system 800, return air flow control damper 922 splits the return air into a first portion to be recirculated, and a second portion to be exhausted. Airflows within manifolds 910, 912, and/or 914 may be integrated with an appropriate air flow header system to direct the airflows into and out of the appropriate sets of sub-channels within the exchanger modules 902. However, unlike in system 800, in system 900 this split occurs after the return air has been used to recondition the supply air, rather than before. A return air fan 920 also may be used to help control the flow of return air through the system.

The examples described above each highlight various features that distinguish the examples from each other. Generally, any of the features described in the different examples, along with any of the general principles described above in Section II, may be used in combination with each other to construct a heat and moisture exchange system according to the present teachings, even if the exact combination is not explicitly described in an example. 

What is claimed is:
 1. A system for enabling heat and moisture exchange between air streams entering and leaving a building, comprising: a modular exchanger partition including a plurality of modules disposed on a building rooftop, each module defining an interior channel; a membrane, permeable to water vapor and substantially impermeable to constituent gases of air, disposed within each module and dividing the interior channel of the module into a first sub-channel through which a first air stream may pass and a second sub-channel through which a second air stream may simultaneously pass; a plurality of supply air inlets, each configured to allow ingress of supply air from an environment external to the building into one of the first sub-channels; a return air manifold configured to receive return air from an interior environment of the building and to direct a portion of the return air into each of the second sub-channels; and a supply air manifold configured to receive reconditioned supply air from each of the first sub-channels and to direct the reconditioned supply air from the first sub-channels to an air conditioning unit disposed on the building rooftop.
 2. The system of claim 1, further comprising a plurality of reconditioned return air outlets, each providing egress of reconditioned return air from one of the modules into the environment external to the building.
 3. The system of claim 1, wherein the return air manifold includes a return air flow control damper configured to receive return air that enters the return air manifold, to direct a first portion of the return air toward the air conditioning unit, and to direct a second portion of the return air into the second sub-channels.
 4. The system of claim 3, wherein the return air flow control damper is further configured to provide control over the rate of return air flowing into the return air manifold.
 5. The system of claim 3, wherein the return air manifold defines a cross-sectional area that decreases as the manifold extends away from the flow control damper and toward each successive module.
 6. The system of claim 1, further comprising a reconditioned return air manifold configured to receive reconditioned return air from each of the second sub-channels and to direct the reconditioned return air toward a return air flow control damper.
 7. The system of claim 6, wherein the return air flow control damper is configured to direct a first portion of the reconditioned return air into the air conditioning unit, and a second portion of the reconditioned return air into the environment external to the building.
 8. The system of claim 7, wherein the reconditioned return air manifold defines a cross-sectional area that increases as the reconditioned return air manifold extends from each successive module toward the return air flow control damper.
 9. The system of claim 1, wherein the supply air manifold defines a cross-sectional area that increases as the supply air manifold extends from each successive module toward the air conditioning unit.
 10. An apparatus for enabling heat and moisture exchange between air streams entering and leaving a building, comprising: a partition configured to be disposed outside a building in the vicinity of an air conditioning unit of the building, the partition defining an interior channel; a membrane disposed within the partition and dividing the interior channel into a first sub-channel through which an incoming air stream may pass and a second sub-channel through which an outgoing air stream may simultaneously pass; a fresh air inlet configured to allow ingress of fresh air into the first sub-channel; an exhaust air outlet configured to allow egress of exhaust air out of the second sub-channel; a supply air conduit configured to connect the first sub-channel to a supply air port of the air conditioning unit, and thus to transport the incoming airstream from the partition to the supply air port; and a return air conduit configured to connect the second sub-channel to a return air port of the air conditioning unit, and thus to transport the outgoing airstream from the return air port to the partition; wherein the membrane is permeable to water vapor and substantially impermeable to constituent gases of air.
 11. The apparatus of claim 10, further comprising a supply air flow control damper disposed between the supply air conduit and the supply air port, and a return air flow control damper disposed between the return air conduit and the return air port.
 12. The apparatus of claim 11, further comprising a supply air fan disposed between the partition and the supply air port, and a return air fan disposed between the partition and the return air port.
 13. The apparatus of claim 10, wherein the partition includes a plurality of substantially identical partition modules, the supply air conduit connects the first sub-channel of each module to the supply air port, and the return air conduit connects the second sub-channel of each module to the return air port.
 14. The apparatus of claim 13, wherein the supply air conduit defines a length dimension corresponding to a direction of air flow from the partition toward the supply air port, and a cross-sectional area of the supply air conduit increases along the length dimension to accommodate supply air received from successive modules.
 15. The apparatus of claim 13, wherein the return air conduit defines a length dimension corresponding to a direction of air flow from the return air port toward the modules, and a cross-sectional area of the return air conduit decreases along the length dimension as the return air passes into successive modules.
 16. A system for enabling heat and moisture exchange between air streams entering and leaving a building, comprising: a partition defining an interior channel and disposed on a building rooftop; a membrane, permeable to water vapor and substantially impermeable to constituent gases of air, disposed within the partition and dividing the interior channel into a first sub-channel through which a first air stream may pass and a second sub-channel through which a second air stream may simultaneously pass; a supply air inlet configured to allow ingress of supply air from an environment external to the building into the first sub-channel; a return air inlet configured to receive return air from an interior environment of the building and to direct at least a portion of the return air into the second sub-channel; a supply air outlet configured to allow egress of reconditioned supply air from the first sub-channel; a return air outlet configured to allow egress of reconditioned return air from the second sub-channel; and a supply air conduit fluidically connecting the supply air outlet to an air conditioning unit disposed on the building rooftop, and configured to transport reconditioned supply air from the supply air outlet to the air conditioning unit.
 17. The system of claim 16, wherein the return air inlet is configured to direct substantially all of the return air into the second sub-channel.
 18. The system of claim 17, further comprising a return air flow control damper configured to receive reconditioned return air from the return air outlet, to direct a first portion of the reconditioned return air toward the air conditioning unit, and to direct a second portion of the reconditioned return air into the environment external to the building.
 19. The system of claim 16, further comprising a return air flow control damper configured to receive return air from the return air inlet, to direct a first portion of the return air toward the air conditioning unit, and to direct a second portion of the return air into the second sub-channel.
 20. The system of claim 19, wherein substantially all of the second portion of the return air passes through the second sub-channel and then passes out of the return air outlet and into the environment external to the building as reconditioned return air. 